Electronic mail (“e-mail”) messages may be generally encoded using one of a number of known protocols to facilitate secure message communication. The Secure Multiple Internet Mail Extensions (“S/MIME”) protocol, for example, relies on public and private encryption keys to provide confidentiality and integrity, and on a Public Key Infrastructure (PKI) to communicate information that provides authentication and authorization. Data encoded using a private key of a private key/public key pair can only be decoded using the corresponding public key of the pair, and data encoded using a public key of a private key/public key pair can only be decoded using the corresponding private key of the pair. In S/MIME, the authenticity of public keys used in the encoding of messages may be validated using certificates. Other known standards and protocols may be employed to facilitate secure message communication, such as Pretty Good Privacy™ (PGP) and variants of PGP such as OpenPGP, for example. It is understood that as compared to S/MIME-based systems, PGP-based systems also utilize public and private encryption keys to provide confidentiality and integrity, although the authenticity of public keys used in the encoding of PGP messages are validated in a different manner. Constructs for providing a public key and information on the key holder similar to that of a “certificate” (as used in S/MIME for example) may be provided in such other secure message communication standards and protocols. One such construct is commonly known as a “PGP key” in PGP-based systems. For the purposes of this specification and the claims, the term “certificate” may be deemed to include such constructs.
Generally, before a new e-mail message that has been composed by a user of a computing device can be sent, it may be necessary to retrieve certain data to process the message, including for example: (1) security policy data, which may identify a required security encoding for the message; (2) certificate data, which typically includes a certificate holder's public key and other identification information associated with the certificate holder; and/or (3) certificate status data, which may be used in verifying the status of a certificate (e.g. whether the certificate has been revoked). While an e-mail message is being composed, it is typically in a dynamic state until it is sent. Accordingly, only after the user has finished composing the e-mail message and directed the computing device to send the message (e.g. by selecting a “send” option provided by a messaging application) would the data typically be retrieved and used to further process the message before it is sent. This avoids unnecessary requests for the data, which might be made if the user who is composing a message ultimately decides not to send the message, for example.